Lawyers for two Americans jailed as enemy combatants in the war on terror went before the U.S. Supreme Court Wednesday to challenge President Bush's right to indefinitely detain their clients. The legal case could have a far-reaching impact on the power of the government to detain its own citizens at a time of war.

At issue are the cases of Yaser Esam Hamdi and Jose Padilla. Mr. Hamdi was captured on the battlefield in Afghanistan while Mr. Padilla was arrested in Chicago in connection with an alleged al-Qaida bomb plot.

Both men are U.S. citizens who have been held for nearly two years by the military as enemy combatants in the war on terror and only recently were granted access to lawyers.

Frank Dunham is Mr. Hamdi's attorney. In oral arguments before the Supreme Court, he said that President Bush has overstepped his authority by detaining his client indefinitely without trial.

"I would urge the court to find that citizens can only be detained by law and here there is no law," he said. "If there is any law at all, it is the executive's [president's] own secret definition of whatever "enemy combatant" is. And do not fool yourselves into thinking that that means somebody coming off a battlefield because they have used it [in courts] in Chicago, they have used it in New York and they have used it in Indiana."

A lawyer for the Bush administration argued that the president does have the right to order the detention of terror suspects who are deemed a threat even if they are American citizens.

"There are troops still on the ground in Afghanistan," he said. "It makes no sense whatsoever to release an individual detained as an enemy combatant in Afghanistan while the troops are still on the ground in Afghanistan."

However, several of the high court justices seemed to be troubled by the administration's contention that it can indefinitely detain an American citizen without providing legal counsel or a trial.

In an exchange between Mr. Clement and Supreme Court Justice Sandra Day O'Connor, Mr. Clement said,"If they are just being held in a preventative detention then, in that circumstance, they are not entitled to counsel."

Justice O'Conner responeded,"But have we ever had a situation like this where presumably this status, war-like status, could last for 25 years? 50 years? Whatever it is."

Some legal experts who support the administration on detaining enemy combatants predict the high court will rule in the president's favor.

"The president's obligation is to prevent ongoing attacks by intercepting the people who are carrying them out," said Ruth Wedgwood, a legal expert at Johns Hopkins University's School of Advanced International Studies here in Washington. "And we are not talking here about fundraising or pizza [delivery] boys or people who took an al-Qaida guy in for the night. In [Jose] Padilla's case, we are talking about somebody who was allegedly in the very course of carrying out an attack."

However, administration critics are confident that the high court will decide that the president has gone too far in denying legal rights to U.S. citizens, even during a time of war.

"They [the Bush administration] have created a legal limbo, which is without precedent, and this basically rests on a claim that the president gets to do whatever he wants to do here and ignore the legal rules that have developed over the centuries because we are fighting the war against terrorism," said Steven Shapiro, who is with the American Civil Liberties Union. "In my view, that is the wrong way to fight the war against terrorism and the end, I think, is going to be horribly counterproductive."

The Supreme Court is expected to issue rulings in both the Hamdi and Padilla cases by the end of June.

Last week, the court heard arguments about whether the 600 or so enemy combatants held at a U.S. Naval base in Cuba should have access to the U.S. legal system. That case will also be decided sometime in the next two months.